1. Field of the Invention
This invention relates to a disposable diaper in which tape tabs are continuously connected respectively to opposite lateral side portions of a rear waist body portion. Each tape tab is provided with a projection member or a recess member of a mechanical fastener, and a counterpart portion for retaining the projection member or recess member of the mechanical fastener. The counterpart portion is provided on the stomach side. More particularly, this invention relates to a disposable diaper having a fastener in which the rear waist body portion can positively be attached to or retained by the stomach side without peeling paper, and in a disposable form where the form or shape of the diaper ready to be disposed can be easily and positively maintained.
2. Description of the Related Art
A disposable diaper has been known which comprises a liquid permeable topsheet, a liquid impermeable backsheet, and an absorbent member interposed therebetween. It has a front waist body portion which is located on the stomach side and a rear waist body portion which is located on the back side of the diaper wearer. During use, the opposite side areas of the rear waist body portion are retentively attached to the stomach side by a mechanical fastener. In such a disposable diaper, a projection member or a recess member of the mechanical fastener is provided on each tape tab which is connected with each of the opposite lateral side areas of the rear waist body portion. A counterpart portion is provided on the stomach side and adapted to retentively engage the projection member or recess member of the mechanical fastener.
Compared to a diaper in which the rear waist body portion is retentively attached to the stomach side by an adhesive fastener, a disposable diaper of the above-mentioned type has such advantages that: degradation of a retentive attaching force caused by contamination due to powder or the like is less likely to occur. Accordingly, there is no fear that the front waist body portion does not become easily separated from the rear waist body portion when the former is to be peeled off the latter, preventing breakage of the backsheet of the front waist body portion. When peeling the mechanical fastener, the rear waist body portion can easily be peeled off the front waist body portion and reducing the possibility of tearing of the backsheet at the front waist body portion.
However, in such a conventional disposable diaper, it is difficult to retentively attach the tape tabs to other areas than the counterpart portion. Accordingly, a disposable form of the conventional diaper, which is formed by rolling up the disposable diaper so that the absorbed liquid or the like will not leak inwardly, is difficult to maintain when the conventional disposable diaper is to be disposed.
In order to obviate the above inconveniences, there is proposed a technique, as discussed in Japanese Patent Application Laid-Open Nos. 4372/1990 and 4373/1990, in which each tape tab is provided with both a mechanical fastener portion functioning as a mechanical fastener and an adhesive portion functioning as an adhesive fastener.
Specifically, in Japanese Patent Application Laid-Open No. 4372/1990, as shown in the attached FIG. 12A, the tape tabs 713 are further allowed to extend beyond the mechanical fastener portions 713a. An adhesive agent is applied to the same surface as the mechanical fastener portions 713a to form adhesive portions 713b. The adhesive portions 713b are placed one upon the other in a superimposed relation, which is further folded upon the mechanical fastener portions 713a, or as shown in the attached FIG. 13, each tape tab 813 is provided only with an adhesive portion 813b, and a mechanical fastener piece 813a is peelably attached to this adhesive portion 813b. Also, in the Japanese Patent Application Laid-Open No. 4373/1990, as shown in the attached FIG. 14, one surface of each tape tab 913 is provided with a mechanical fastener portion 913a and with an adhesive portion 913b so that both the mechanical fastener portion 913a and the adhesive portion 913b are retentively attached to the stomach side when the diaper is put on the diaper wearer.
As shown in the attached FIG. 12A, with respect to the technique in which the tape tabs 713 are further allowed to extend beyond the mechanical fastener portions 713a to form the adhesive portions 713b, for disposing the disposable diaper, as shown in the attached FIG. 12 B, each tape tab 713 is developed to allow the adhesive portion 713b to be exposed. This adhesive portion 713b is attached to the backsheet (not shown) which is located outwardly in the disposable form, thus enabling to maintain the disposable form. However, in the disposable form, since the area provided with the mechanical fastener portion 713a is arranged on the backsheet side and is not firmly secured to the backsheet (not shown), the tape tabs 713 are difficult to retain on the backsheet (not shown) and the disposable form is difficult to be maintained in its favorable condition.
On the other hand, with respect to the technique of the attached FIG. 13, in which the mechanical fastener piece 813a is peelably attached to the adhesive portion 813b, the adhesive portion 813b can be exposed by peeling off the mechanical fastener piece 813a and the disposable form can be maintained by this adhesive portion 813b when the disposable diaper is to be disposed of. However, it still involves another problem in that much time and labor is required to dispose the mechanical fastener piece 813a.
Furthermore, as shown in the attached FIG. 14, with respect to the technique in which both the mechanical fastener portion 913a and the adhesive portion 913b are provided on one surface of each tape tab 913, the disposable form can be maintained by attaching the adhesive portion 913a directly to the corresponding tape tab and the backsheet (not shown) when the disposable diaper is to be disposed. However, since the adhesive portion is used when the diaper is worn, there remains the aforementioned problems inherent in the prior art, in which the retentive attaching force is degraded by contamination due to powder or the like and the front waist body portion does not easily separate from the rear waist body portion when the former is to be peeled off the latter. This results in breakage of the backsheet of the front waist body portion. When this occurs, reengagement of the stomach side with the back side is very difficult to perform.